APPLICATION OF ION-PAIR COMPLEXES OF SOME ACID-BASE INDICATORS IN PHARMACEUTICAL ANALYSIS .1. SPECTROPHOTOMETRIC MICRODETERMINATION OF L-HYOSCINE BUTYL BROMIDE BY ITS ION-PAIR COMPLEX WITH METHYL-ORANGE

The ion pair complex of L-hyoscine butyl bromide I with methyl orange II was formed in an AcOH-AcONa buffer solution (pH 4.20) and immediately extracted quantitatively with chloroform. This chloroform solution of the ion pair complex shows a lambdamax at 415 run. Its molar absorptivity and Sandell's sensitivity were calculated as 8.96 x 10(3) Lmol-1cm-1 and 49 ng of I/cm2 respectively. Beer's law was obeyed for 15-50 mug of I/ml (about 34.0-113.0 mumol of I/L). The studied complex was later successfully used for the spectrophotometric determination of I in micromolar concentrations, either in pure form or in a two-component injectable solution in the presence of Acetaminophen (Paracetamol) and in a molar ratio of the two components of 1:87.5 (L-Hyoscine butyl bromide: Acetaminophen). The accuracy and precision of proposed method was experimentally investigated and evaluated, in both cases, and the obtained results were fully satisfactory.